Alright, remember that the first?s wood technique is unique. Now Tenzō (codenamed Yamato) is capable of using this technique via Orochimaru's gene therapy experiments. So here?s my question: Why doesn?t Oro simply use gene therapy and create an endless supply of bodies that can use Sharingan? He wouldn?t have done this for Kimimaro as he thought the experiment failed and now Kimimaro?s body is probably lying in some laboratory hidden within Konoha (think back to Sakura?s explanation of hunter nin?s). However, now that he knows Tenzō lived he could easily try the experiment again with Sasuke's genes. He doesn?t exactly respect the value of human life so there isn?t any reason why he couldn't run endless experiments until he has as many containers as he wishes. So why does he need Sasuke anymore?